2009-02-16

Spirit Sol 43

We did so much work yestersol, and hardly anything has happened yet. This is as expected, since most of the work was in overnight operations that haven't run yet -- or, rather, that hadn't run at the time we had our comm pass. But so far, the news is good.

Assuming our sequences run successfully, tomorrow will be a pure driving sol. When we get the images that show us where we are, we'll plan the longest drive we can, then come in tomorrow afternoon (rover time) for an afternoon "megadrive." In preparation for this, Chris Leger brings me up to speed on the architecture they've come up with. It isn't quite the way I would have done it, but it's perfectly cromulent. We'll uplink forty or so sequences tomorrow, then when we know which ones we want to use for the megadrive, we'll uplink a small bridge sequence to invoke the autonav and a real-time command to start the drive. The bridge sequence also needs to fiddle with the driving time-of-day limit, which has been a bit of an annoyance for us, but it'll be fine.

It falls to me to give the uplink team a briefing on this plan. So once I understand it myself, I go to the SMSA, strap on a headset, and explain it. (Which is needlessly hard to do -- I think my way of arranging things would have been clearer -- but then again, that's just me being an asshole. It's perfectly cromulent.) I discover once more that I can no longer have a meaningful technical conversation without recourse to a whiteboard. They raise one of the projection screens for me, showing the whiteboard behind it, and that helps a lot.

Unfortunately, this causes me to miss the downlink assessment meeting. They won't have much to talk about anyway -- or so I assume -- since most of yestersol's data hasn't arrived, and tomorrow will be almost exclusively a driving sol, with very little science if any.

The SOWG meeting bears this out. We really have just one science request, to image the area immediately in front of the rover just before the drive completes. Chris was already aware of this and has built it into the megadrive sequences, so I don't really need to do anything to support it.

Today's main activity is about 18m of carefully planned driving, in which we must thread our way through several nearby obstacles to get to a reasonably safe zone to start tomorrow's megadrive process. This wouldn't be too bad, but it takes time to get a terrain mesh from MIPL that we can use for the driving. We have one that gives good coverage of the area immediately around the rover, and one that has decent coverage of the mid-field, but nothing really good for more than 10m or so out, and nothing that combines the near and far fields in a single mesh. It takes time to work out exactly what we need, and that leaves less time than I'd like for the actual sequencing.

Still, I must be getting better at this, because by the time Bob shows up, I've worked out the terrain mesh issues and I've got a first cut at the drive: we back up a couple of meters, maneuver between a dune (which is not an obstacle but could cause us to slip, which would endanger the rover later in the drive) and a rock, and zigzag between a couple of other obstacles as we head northeast in the general direction of Bonneville. When we get to the edge of the terrain mesh, we turn the rover in Bonneville's direction and turn on the autonav. What's really unusual is that we have to sequence this whole thing before we know the rover's final state. If the overnight and morning sequences we planned yestersol -- which are running now -- don't complete successfully, the drive won't even happen, and we'll have another sol in this spot whether we like it or not. So we might be rushing for nothing. Nevertheless, we have no choice but to proceed.

Bob seems a little nervous about the complex drive. He's obviously more comfortable sequencing the IDD -- he should be, he wrote the software for it -- but he's game. I sympathize with his feelings, though; it's exactly how I felt about both driving and IDDing when we started.

We decide to try to learn from previous experience and hand over the sequencing to Bob earlier. This frees me to fix up some minor problems I noticed in the megadrive sequences, which we'll be using for the first time tomorrow. At some point I find myself in the zone, which hasn't happened for a while: I'm kicking out code like breathing. This feels good.

What with one thing and another, I end up staying well past the end of my shift -- again. This is a problem I need to solve. And I have to come in early tomorrow, almost 4 hours early -- 11:30 rover time, not 15:00 -- to do the megadrive. Despite all of this, I'm weirdly energetic and happy. It might be fatigue, or it might not.

And it's oddly comforting to know I'm not the only one who has a complex task to struggle with. Even though the day was supposed to be simple, the engineering requests and imaging science added up to make it a complicated day after all. During the handover, Kevin Talley asks despairingly, "Why does every sol have to be an intelligence test?" At least we're passing.